优化号主交接超时卡死问题

- 号主交接超时(owner_timeout)后允许补提交交接说明，避免临时延误导致订单卡死
- 后台新增"重置交接"动作，可将超时订单恢复为待号主交接并刷新计时
- 交接超时改以进入待交接时刻为基准计算，新增 handoff_started_at 字段

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/internal/modules/order/handoff.go

@@ -20,9 +20,12 @@ func (r *Repository) SubmitHandoff(ctx context.Context, userID uint64, orderID u
 		if order.OwnerID != userID {
 			return ErrPermissionDenied
 		}
-		if order.Status != orderStatusPendingHandoff || order.HandoffStatus != handoffStatusPendingOwner {
+		// 号主交接超时（owner_timeout）后仍允许补提交，避免临时延误导致订单卡死。
+		if order.Status != orderStatusPendingHandoff ||
+			(order.HandoffStatus != handoffStatusPendingOwner && order.HandoffStatus != handoffStatusOwnerTimeout) {
 			return ErrOrderCannotHandoff
 		}
+		lateSubmit := order.HandoffStatus == handoffStatusOwnerTimeout
 		record := model.HandoffRecord{
 			OrderID:    order.ID,
 			FromUserID: order.OwnerID,
@@ -35,11 +38,15 @@ func (r *Repository) SubmitHandoff(ctx context.Context, userID uint64, orderID u
 		}
 		order.HandoffStatus = handoffStatusPendingRenterConfirm
 		orderID := order.ID
+		renterContent := "请查看交接记录，确认账号可正常登录后点击确认收号。"
+		if lateSubmit {
+			renterContent = "号主已补交交接说明，请查看交接记录，确认账号可正常登录后点击确认收号。"
+		}
 		if err := notification.Append(tx, notification.Entry{
 			UserID:  order.RenterID,
 			Type:    "handoff",
 			Title:   "号主已提交交接说明",
-			Content: "请查看交接记录，确认账号可正常登录后点击确认收号。",
+			Content: renterContent,
 			BizType: "order",
 			BizID:   &orderID,
 		}); err != nil {